Key Takeaways

  • Researchers at Carnegie Mellon University used skin as a conductor of electricity, to power tiny, battery-free wearable electronics.
  • The technique was built around the concept of user-friendly components and implementations.
  • Power-over-skin technology still needs further development, but stands to benefit the differently abled, or individuals with chronic health conditions in the future.




Occasionally, you’ll see a headline touting some groundbreaking battery technology advancement, only for it to be a theoretical concept that’s years from reality. But what if we could untether devices from their batteries, and transmit just enough wireless electricity to feed smartwatches, smart rings, and other low-power devices just the trickle of energy they need to keep functioning?

That’s what a group of researchers in Carnegie Mellon University’s Future Interfaces Group asked, as they worked to demonstrate the first use of the human body — its skin, to be exact — to move electricity from a battery stored in a pocket, to a device worn elsewhere. The proof-of-concept of power-over-skin might not end up in your favorite product next week, but it’s already reality.



Using the human body as a conductor

Without electrocuting anybody, or stopping anybody’s heart

Electronic earrings are among the devices the researchers used as demonstrations.

Associate Professor Chris Harrison, PhD student Daehwa Kim, and gap year graduate student Andy Kong recently published their work on power-over-skin, a groundbreaking use of skin as a conductor of electricity, for powering tiny, battery-free wearable electronics.

It isn’t one of those theoretical-yet-hopeful advancements, either. The group framed their project from a real-world perspective from the start, considering only convenient components like dry electrodes, which don’t require sticky conductive gel to connect to the body’s electrical field. The team built on prior research indicating the body’s efficient transfer of RF wireless energy at 40 MHz, a frequency high enough to stay undetected by sensitive nerve endings that would otherwise scream from electrocution.


After thoroughly vetting their implementations, they tested various transmitter locations, even taking into account the separation of two layers of fabric that exist between a pocketed power supply and the skin. They managed to safely deliver over 100 µV to the left bicep from a transmitter located in a left-hand pants pocket, in one example.

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The researchers targeted devices like thumb-operated Bluetooth LE joysticks and skin-attached health sensors using capacitors, rather than batteries, to maximize efficiency. Taking advantage of sleep-wake cycles, they successfully demonstrated power-over-skin’s effectiveness at powering health sensors, without a single external wire involved.


To be clear, 100 µV isn’t much. The technology has a long way to go before it could impact wearables like smart rings and their roughly 0.5Wh batteries. But it could have a beneficial impact on, for example, the differently abled, or those living with chronic health conditions, in the relatively near future. This isn’t the first time in recent tech news that up-and-coming innovators have created something really cool. Here’s hoping their research serves as a springboard for inventors around the world, as soon as possible.

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